We are looking at a 30' Sundowner Tug, but are new to this size of boat. The deceased previous owners son tells us that they have always left the wet exhaust seacock in the open position because since the seacock and the exhaust are almost at the same level, nothing would happen.

Every fibre of my being says this is wrong.

The seacock is located 1/2 way between the keel and the waterline beside the engine amidships, and the exhaust terminates just above the waterline aft. If any link in the chain between the two were to fail, wouldn't it at least flood the engine room...maybe even sink the boat?

Like I said...rookie here!

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__________________"The most interesting path between two points is not a straight line" Murray Minchin

We are looking at a 30' Sundowner Tug, but are new to this size of boat. The deceased previous owners son tells us that they have always left the wet exhaust seacock in the open position because since the seacock and the exhaust are almost at the same level, nothing would happen.

Every fibre of my being says this is wrong.

The seacock is located 1/2 way between the keel and the waterline beside the engine amidships, and the exhaust terminates just above the waterline aft. If any link in the chain between the two were to fail, wouldn't it at least flood the engine room...maybe even sink the boat?

Like I said...rookie here!

Always close your seacocks when leaving the boat.

I don't do it when I leave to go to shore and walk around, but I do close them when leaving the boat for an extended period of time.

There are two schools of thought on closing engine RW seacocks. Some don't because the danger of forgetting to open and damaging the engine. I've heard of mechanics and boat watchers (another active thread on this Forum) not taking the time to insure seacock open and creating damage. I had a dock mate whose vessel was stolen for short joy ride, he was so happy he left his seacocks open. On a well found boat with good hoses and an attentive owner I can see both sides. I'm lucky in that all my active through hulls are in one location. Strangely, non engine through hulls are more "deadly" that engine through hulls from insurance claims - such as heads, watermakers, ACs, cold plate reefers, salt water wash down pumps, deck drains that go into bilge, leaving a high pressure water hose connected to the on-board water system etc.

And not to mention the sad cases where the through hull fitting fails when being closed, so lots to go wrong either way you choose.

Maybe I'm misreading what the OP posted but it sounds to me as though the "seacock" is located away from the opening in the hull. In that case its just a valve. To function as a seacock it needs to be at the through-hull. During our haulout this spring I realized that our genset was plumbed directly to a through-hull with no seacock. The yard didn't seem to think it was any big deal but I put in a seacock anyway because it made me feel better. If the OP truly has a valve lying in the bilge halfway between the through hull and the engine that would really concern me - if anything happens to that line from the valve to the hull that could be a sinking event.

There are two schools of thought on closing engine RW seacocks. Some don't because the danger of forgetting to open and damaging the engine.

And not to mention the sad cases where the through hull fitting fails when being closed, so lots to go wrong either way you choose.

When I close my seacocks I put a "seacocks closed" notice attached to the ignition keys and the generator control panel.

Another very good thing about closing your seacocks is that movement keeps them operational. Seacocks seem to get stiff to a point of being inoperable through disuse. Using them insures they are in good working order.

All of my seacocks are in the engine room within probably 10' of each other. I close them and open them all at the same time.

Another very good thing about closing your seacocks is that movement keeps them operational. Seacocks seem to get stiff to a point of being inoperable through disuse. Using them insures they are in good working order.

Excellent point Kevin and sadly overlooked by many if not most, judging purely from the boats for sale I've looked at. The most dangerous thing on a boat IMO is a valve that is not regularly exercised. Regular exercise also keeps the operator intimately aware of their location and function in an emergency.

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Craig

It's easier to fool people than to convince them that they've been fooled - Mark Twain

We leave our main engine intake seacocks open all the time. I excersise them every couple of months. If we do close one or both of them for some reason we tape the power lever back with gaff tape and hang a sign on it that says the seacock for that engine is closed.

I installed red safety covers over the toggle switches that control the generator starter and our big AC salt water washdown pump. The flip-up covers say "seacock" on them. When I open the seacocks for these pieces of equipment we flip up the safety cover (we have to to operate the equipment) and leave that cover open until we close the seacock as a reminder on the AC panel that the seacock(s) are open.

When I close my seacocks I put a "seacocks closed" notice attached to the ignition keys and the generator control panel.

Another very good thing about closing your seacocks is that movement keeps them operational. Seacocks seem to get stiff to a point of being inoperable through disuse. Using them insures they are in good working order.

Same here. As an ex-submariner, I have an affinity for working thru-hull valves and close them if they are not required to be open.

The most dangerous thing on a boat IMO is a valve that is not regularly exercised. Regular exercise also keeps the operator intimately aware of their location and function in an emergency.

Before someone post a photo of a valve on a lead going for a walk, I totally agree, closing them when leaving the boat for any appreciable time.
It is said here sailboats close them, powerboats leave them open; not me. And yes, valves like regular use. Not good forcing a valve,not knowing what might happen.

You actually have a seacock on your exhaust?
If the line is not self draining, I would close it. otherwise it seems extra.

Depends if its a fully marinized engine doesn't it?. Mine isnt. The engine I have is a Perkins 6.354 Diesel. Whilst they have made full marine versions of the type of engine with built in heat exchanger, wet exhaust and some other minor things, they are basically the same. mine is out of a Qantas Airlines truck ( the ones that push the planes back so they can taxi ).

My exhaust will be bone dry. I wont have any running water through it at all. The system I will be running is a closed water system on the engine with sea water cooling. I have an external heat exchanger that runs fresh water coolant in her for the engine, I have a belt driven fynnspray sea water pump that will suck sea water up and push it in to and through the engine heat exchanger, the down and through to the gearbox heat exchanger and then over to and through the engine oil heat exchanger before exiting through a through hull right beside the cockpit. When the boats running, I will be able to just poke my head out the window and see a stream of water coming out.

Whilst I will have a seacock on the sea water intake, I won't be closing it if I'm on her. There's no real point is there? Unless a line fails then in which the auto bilge pumps will kick in and the high water alarm will sound if the pumps can't keep up. If I was to leave her on the mooring for an extended period of time then I'd shut it but yeah.

Regardless of leaving them open or closed. It's good practice to open and close them during the monthly checks to make sure they don't cease.

Hendo -- Your setup will still sink your boat if hoses or fittings go bad, no different than any other through hull drawing from below the waterline. Relying upon a bilge pump to operate for an extended period if not on shore power is foolhardy and optimistic if on shore power. (Even the Bounty's bilge pumps couldn't keep her afloat)

Bruce K's vessel is on a mooring with all through hulls properly closed, the only way to go in his case.

FF wins no prize from the many of us who have keyless push button start